Agricultural operations are being driven toward higher levels of cost efficiency and risk management due to narrower profit margins and higher input costs (e.g., seeds, fertilizer, chemicals). For this reason, it is desirable to dispense in a single-pass operation both seeds and fertilizer or other treatment relevant to the successful development or growth of the seeds in order to reduce fuel costs and minimize wear on machinery and equipment. However, combining these operations requires managing certain risks. On the one hand, dispensing too much fertilizer can result in “seed burn” or fertilizer toxicity which can increase seedling mortality. This can occur when the concentration of fertilizer (which usually contains a combination of nitrogen, phosphorus, potassium, and sulfur) near the seed is too high and poisons the seed, which prevents germination and growth. On the other hand, dispensing too little fertilizer can also lead to the loss of valuable production capacity due to a lack of nutrients available to the growing plants.
To manage these risks, a method that coordinates the dispensation of seeds and fertilizer or other treatment is used. One such method involves two separate application devices, one for seeds and one for fertilizer, mounted on the same implement frame. These devices may include one shank or disc-style opener to apply the seeds and another shank or disc-style opener to apply the fertilizer, and may operate by dispensing seeds in one set of spaced-apart rows and dispensing fertilizer in another set of rows that are alternatingly interposed between the seed rows. However, this suffers from several disadvantages, including added equipment cost associated with having separate openers, added fuel cost associated with pulling the additional openers, and problems with immobile nutrients (e.g., sulphur) being applied several inches away from the seed rows.
Another method involves using a “double shoot” boot to dispense both seeds and fertilizer through different outlets of the same boot. However, this also suffers from disadvantages, including a lack of proper separation between the seeds and the fertilizer due to variation in the final resting places of seeds and fertilizer as they leave the boot. In particular, seeds can bounce away from their intended positions into direct contact with fertilizer, and, similarly, fertilizer granules can bounce away from their intended positions into direct contact with seeds. Also, due to their complexity, many such boots are easily plugged with soil when used in wet conditions, which can result in poor penetration, poor seed placement, and excess draft loads on the drill, and, in general, interfere with the proper dispensation of seeds or fertilizer. Relatedly, many such boots can accumulate so much soil when used in wet conditions that they become too large and bulky to effectively penetrate the ground and properly place the seeds and fertilizer. Additionally, many such boots are initially configured to meet the user's immediate needs, and are difficult or impossible to reconfigure if those needs change. For example, if the user selects a boot configured to primarily deliver granular fertilizer and secondarily deliver liquid fertilizer, it may be difficult or impossible to later switch to delivering anhydrous ammonia.
This background discussion is intended to provide information related to the present invention which is not necessarily prior art.